In recent years, developments of techniques for analyzing solution samples employing microchips have been progressed. In particular, analyses, in which a plurality of constituents in a solution are separated by employing micro passages provided in the microchip and then each of the constituents are detected via various types of detecting techniques, are implemented. A typical exemplary implementation for employing a mass spectrometer as a detecting technique includes a process for analyzing peptide mixtures or the like with a mass spectrometer employing an electro-ion spray ionization after the peptide mixtures or the like are separated via a liquid chromatography (Non-Patent Literature 1).
When a mass spectrometer is employed as a detecting technique, a precision measurement is achieved by measuring a reference material having a known weight prior to measuring samples and then conducting a calibration of the apparatus. In such case, in an electro-ionspray process, a calibration is first carried out by employing the reference material, and then measurements of samples for mass spectrometry are conducted. Since a position of an exhaust-nozzle for an ionized sample is fixed in the electro-ionspray process, once a calibration is achieved, and then theoretically, the measured values do not so greatly deviate when the measurements of samples are sequentially conducted without changing the condition.
On the other hand, another typical ionization process may be a mass spectrometry technique employing a matrix assisted laser desorption/ionization (MALDI) process. The MALDI process is one of processes, in which samples having relatively larger molecular weight such as proteins and the like can be ionized without decomposing thereof.
In a MALDI process, a target plate of several centimeters-square is ordinarily employed, as shown in FIG. 12. A target plate 210 as show in FIG. 12 is, for example, several centimeters-square, and is provided with a plurality of shallow wells 255.
A sample is dropped in the well 255, and further, a matrix serving as an ionization accelerator is dropped therein to prepare a sample for mass spectrometry. Then, the sample for mass spectrometry on a target plate is transferred to a laser spot position by employing an electric stage to conduct a mass analysis.
[Non-Patent Literature 1]
E. Gelpi, Journal of Mass Spectrometry, 37, 241-253.
[Non-Patent Literature 2]
M. L. Mok and additional four persons, The Analyst, 2004, 129, 109-110.